feat: enhance ChatMessage loading state management (#6196)

🔧 (chat-message.tsx): add isBuilding variable to track if the chat message is being built to improve user experience

Co-authored-by: anovazzi1 <otavio2204@gmail.com>
Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@langflow.org>

src/frontend/src/modals/IOModal/components/chatView/chatMessage/chat-message.tsx

@@ -313,8 +313,10 @@ export default function ChatMessage({
                 contentBlocks={chat.content_blocks}
                 isLoading={
                   chatMessage === "" &&
+                  lockChat &&
+                  chat.properties?.state === "partial" &&
                   isBuilding &&
-                  chat.properties?.state === "partial"
+                  lastMessage
                 }
                 state={chat.properties?.state}
                 chatId={chat.id}